1. Field of the Invention
This invention relates to an electronic numerical value setting device which can set numerical values regardless of its connection to or disconnection from an electric power source.
2. Related Art
A conventional electronic numerical value setting device exists in which a numerical value may be set by a keying operation whether or not the device is connected to an electric power source. The numerical value thus set is automatically registered by the device for a predetermined period of time after the keying operation.
However, this conventional electronic numerical value setting device has several disadvantages. The power supply may be interrupted or restored during the keying operation, or during an automatic registering latency time. The automatic registering latency time is that period of time which elapses between the completion of a keying operation and the registering of the numerical value. Power supply interruption during the keying operation or the latency time results in setting an incomplete numerical value. Since the incomplete numerical value set is different from the intended numerical value, erroneous operation of the system results.
In addition, it is also possible that numerical data is registered during the latency time which elapses from the instant that the keying operation is ended until the desired numerical value is automatically registered. The value registered during the latency period before the time instant at which automatic registering normally occurs cannot be easily corrected. Accordingly the setting of the numerical value must be carried out again. This is rather troublesome for an operator.